US3767609A - Process for the salt free manufacture of articles from linear aromatic polyamides in a lactam solvent - Google Patents

Process for the salt free manufacture of articles from linear aromatic polyamides in a lactam solvent Download PDF

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US3767609A
US3767609A US00220898A US3767609DA US3767609A US 3767609 A US3767609 A US 3767609A US 00220898 A US00220898 A US 00220898A US 3767609D A US3767609D A US 3767609DA US 3767609 A US3767609 A US 3767609A
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solution
solvent
polycondensation
temperature
polyamide
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H Lussi
C Berther
R Gabler
J Studinka
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Inventa AG fuer Forschung und Patentverwertung
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Inventa AG fuer Forschung und Patentverwertung
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/02—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
    • C08J3/09—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in organic liquids
    • C08J3/091—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in organic liquids characterised by the chemical constitution of the organic liquid
    • C08J3/096—Nitrogen containing compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
    • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
    • C08G69/26—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from polyamines and polycarboxylic acids
    • C08G69/32—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from polyamines and polycarboxylic acids from aromatic diamines and aromatic dicarboxylic acids with both amino and carboxylic groups aromatically bound
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2377/00—Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers
    • C08J2377/10—Polyamides derived from aromatically bound amino and carboxyl groups of amino carboxylic acids or of polyamines and polycarboxylic acids

Definitions

  • R is an alkyl radical having 14 carbon atoms and n is a whole number between and 7.
  • the present invention concerns articles, like fibres, foils, strips or coatings of linear aromatic polyamides, a process for their manufacture in the absence of inorganic salts, and the solution of the aromatic polyamides used for their production.
  • Fibres, foils, coatings and other endless articles of linear high molecular polyamides which predominantly contain m-phenylene-isophthalamide units are of important technical interest on acount of their high melting point of above 300 0., their heat resistance, non-inflammability and their good mechanical, chemical and electrical properties.
  • Formula I is used, wherein R is an alkyl radical with 1-4 carbon atoms; n is a whole number between 5 and 7; and the hydrogen atoms of the methylene groups may be wholly “or” partly replaced by alkyl groups with 1-4 carbon atoms (salt-free means in the absence of salts which dissolve "in the solvents to be used).
  • the preferred solvent for the aromatic polyamides in accordance with the definition is N-methylcaprolactam and N-ethyl-3,3,S-trimethyl-caprolactam.
  • Other members of'this class of solvents are N-isobutyl-, N-tert.butyl-, N-
  • the preferred polyamide to which the process of the invention may be applied is poly-m-phenylene-isophthalamide.
  • Other co-polyamides can also be used which contain up to 50 mol percent of units derived from p-phenyleneisophthalamide, m-phenyleneterephthalamide, p-phenyleneterephthalamide, m-phenylene 5 methylisophthalamide, hexamethyleneterephthalamide, hexamethyleneisophthalamide, tetramethyleneisophthalamide, dodecamethyleneterephthalamide, or m-phenylene 2,5 dichloroterephthalamide, in the molecule.
  • Polymers of two such units together with at least 50 mol percent of poly-m-phenyleneisophthalamide may form valuable terpolymers.
  • solutions capable of being spun and cast, and containing at least 50 mol percent of mphenyleneisophthalimide units preferably takes place by direct polycondensation of the corresponding diamines with the corresponding acid dihalides, particularly acid dichlorides in the solvent of Formula I, without isolation of the solid polyamide formed.
  • Both the previously known solvents, dimethylacetamide and N-methylpyrrolidone, and the solvents of Formula I used in accordance with the invention have the ability to combine the hydrogen chloride formed in the polycondensation of the corresponding diamide with the acid chloride.
  • a disturbing side reaction may take place, however, in that a part of the acid dichloride reacts with the solvent, spitting off chloride ions before it can react with the diamine.
  • This solvent destruction of the acyl halides is described by H. K. Hall, Jr., Journal of Am. Chem. Soc., 78, 2717 et seq. (1956).
  • the dimethylacetamide previously preferred solvent is not satisfactory in every respect.
  • the solvent containing diamine solidifies to a rigid mass which cannot be rendered homogenous by stirring. If th Solid aromatic dichloride is added to it, a very strongly exothermic reaction takes place spontaneously which with larger charges in the absence of homogenous mixing may lead to overheating, whereby the above mentioned side reaction sets in. It is therefore difiicult to obtain high molecular weights with large quantities. Likewise difiicult is the dissipation of the reaction heat suddenly released in the polycondensation on a technical scale.
  • FIGS. 2a-c these advantages are shown in more detail.
  • the three curves FIGS. 2a, b and c show the timetemperature diagrams of three comparative experiments using the same starting materials, each with /2 mol of m-phenylene diarnine and isophthaloyl chloride in the same concentration using the same apparatus whilst varying only the solvent.
  • the time at which the (solid) isophthaloyl chloride is added is marked by an arrow.
  • the broken line temperature curve indicated that stirring cannot be done in this phase.
  • the cooling bath temperature is shown by the chain lines.
  • the N-methylcaprolactam acts as a moderator for the polycondensation reaction which is very violent in the previously proposed solvents. Relatively, the same effect is observed with other representative solvents of Formula I, e.g. with N-ethylcaprolactam, N-methyl 4 methylcaprolactam and N- methyl 3,3,5-trimethylcaprolactam. Since, with the N- alkylcaprolactams of Formula I the disturbing side reaction between solvent and aromatic acid dichloride only takes place to a small extent, the polycondensation may be carried out in the temperature range between 5 C. and +25 C. The preferred temperature range is '15 C. to 0 C.
  • the polycondensation mixture may be stirred from beginning to end.
  • This advantage and the further fact that the aromatic acid dichlorides are more stable than in dimethylacetamide or N-methylpyrrolidone make it possible to produce polyamides with far higher molecular weights and more reproducibility than with known processes. If one takes the RSV as a measure of the molecular weight of the polycondcnsates obtained, with the use of N-alkyl lactams of Formula I, values of 2.5 to 3.0 are obtained with ease, whilst with the use of dimethylacetamide or N-methylpyrrolidone, as is apparent from the above, values above 2.0 are reached only with difficulty.
  • a further advantage of the use, in accordance with the invention, of solvents of Formula I becomes apparent when the polycondensation solution is freed from the hydrogen chloride formed during the reaction, which is preferably eifected by introduction of gaseous ammonia and filtering off the ammonium chloride formed which is insoluble in the solvents of Formula I.
  • the polycondensation solution is freed from the hydrogen chloride formed during the reaction, which is preferably eifected by introduction of gaseous ammonia and filtering off the ammonium chloride formed which is insoluble in the solvents of Formula I.
  • dimethylacetamide and N-methylpyrrolidone Examples 1 and 2
  • the spinning of solutions of aromatic polyamides in solvents of the Formula I can take place e.g. by the wet spinning process, in which as a precipitation bath a mixture of the same solvent as was used for the polycondensation and water is preferably used.
  • aqueous solutions of inorganic salts like e.g. calcium rhodanide can be used as a coagulation medium.
  • the polyamide solutions used in accordance with the invention are suitable for dry spinning in a hot atmosphere of air or inert gas.
  • a further advantage of the solvents according to the invention arises; they are essentially more stable at elevated temperature even in the presence of airborne acid, and have less tendency to discolor than dimethylacetamide and N-rnethylpyrrolidone.
  • the articles made according to the present process show outstanding mechanical, electrical and thermal properties. Fibres produced in accordance with the invention show tenacities between 4 and 6 g./den., and initial moduli of -150 g./ den.
  • the process of manufacture of the spinning or casting solutions used for this is essentially improved over the prior art since the polycondensation process requires less cooling energy because no solid phases arise as intermediates, and in consequence of lower heat evolution the process can be carried out without danger even with large loads. This holds true particularly for the above-mentioned kind of operation with the use of separate solutions for the reaction components diamine and acid chloride.
  • the addition of inorganic salts to stabilize the solution is unnecessary. Since such salts are not present, even in traces in the end products, these products show better thermal stabiliy and higher values for electrical breakdown resistance.
  • Example 14 Apparatus-The polycondensation is carried out in a cylindrical 1 litre multi-necked flask with flat ground surfaces.
  • the flask is provided with a stainless steel stirrer and a nitrogen inlet tube.
  • the internal temperature is measured with a thermocouple, type Philips Thermocoax 2 ABAC 10 and recorded with a compensation recorder type Texas Instrument Servoriter PWS.
  • a thermocouple type Philips Thermocoax 2 ABAC 10
  • a compensation recorder type Texas Instrument Servoriter PWS For the cooling bath an ultracryostat model Lauda UK40 whose bath temperature is measured with a second thermocouple of the above type and recorded with an automatic compensation recorder Model Philips PR2210 A/2l.
  • Process.54.07 g. (0.50 mol) of m-phenylenediamine are placed in the flask explained above and dissolved under a nitrogen atmosphere with slow stirring in 550 g. of anhydrous dimethylacetamide at room temperature.
  • the flask is then lowered into the cooling bath whose temperature is controlled at --38 C. After expiration of 60 minutes the internal temperature amounts to 28 C. and the diamine solution begins to crystallize. After a further 3 minutes the contents of the flask have solidified and can no longer be stirred (see FIG. 2a, broken line showing the internal temperature).
  • 101.515 g. (0.50 mol) of solid isophthalic acid dichloride is introduced in one portion and wetted with 77 g.
  • the polymer solution becomes cloudy on standing at room temperature with the separation of finely divided solid polyamide and shows after 3 days a reduction in light transmission of about 10% of the initial value (measured in 19 mm. layer thickness in a Lumetron colorimeter Type 402E).
  • the polymer solution becomes cloudy on standing at room temperature and shows after 24 hours a decrease in light transmission of about 10% of the initial value. After 10 days the solution has completely crystallized and no longer transmits light.
  • the isophthalic acid dichloride is evenly distributed in the reaction mixture by stirring but remains for the greater part undissolved at this temperature.
  • the bath temperature is raised (see FIG. 2c).
  • the acid chloride dissolves instantaneously and the internal temperature rises to +35 C. Within 90 seconds.
  • the delayed temperature rise amounts thus, despite a higher bath temperature, only to 43 C.
  • the viscosity of the reaction mixture increases rapidly.
  • the cooling bath temperature is further raised to 5 C. and the condensation mixture stirred for a further 2 hours. Thereafter the flask is placed in an oil bath, heated to C. and the hydrogen chloride neutralized by introduction of gaseous ammonia.
  • the separation of the precipitated ammonium chloride takes place by pressure filtration at 70S0 C.
  • the completely clear and almost colorless solution contains 16% by weight of p0ly-m-phenyleneisophthalamide.
  • a small test portion is treated in the usual way for determination of the reduced specific viscosity.
  • the RSV value amounts to 2.23.
  • the main part of the solution shows, after 12 weeks storage at room temperature, no sign of cloudiness.
  • EXAMPLE 4 In a 6 litre multi-necked flask provided with a stainless steel stirrer, thermometer and gas inlet tube, 259.2 g. (2.398 mol) of m-phenylene diamine are dissolved in 3000 g. of anhydrous N-methylcaprolactam at room temperature whilst introducing nitrogen and stirring. Thereafter the flask is lowered into a cooling bath whose temperature is controlled at -20 C. The water-clear solution is cooled whilst stirring to an internal temperature of 17.5 C. 487.0 g. (2.398 mol) of isophthalic acid dichloride in solid form are introduced and Wetted with 260 g. of N-methylcaprolactarn.
  • the highly viscous solution is freed from ammonium chloride by pressure filtration at l00120 C.
  • the filtered solution is almost colorless and completely clear.
  • the solution contains 14.9% by weight of poly-m-phenyleneisophthalamide.
  • the dynamic viscosity of the solution is 920 poises, measure at 20 C.
  • a small test portion is precipitated in the usual way with water and dried.
  • the RSV amounts to 2.55.
  • the main quantity of the salt-free solution is directly used for spinning experiments.
  • EXAMPLE 5 For the polycondensation the apparatus described in Example 1 is used with an additional dropping funnel. 54.07 g. (0.50 mol) of m-phenylenediamine are placed in the flask and under a nitrogen atmosphere 400 g. of anhydrous N-methylcaprolactam is dissolved with slow stirring at room temperature. The flask is then lowered into a cooling bath controlled at 23" C. and the flask contents cooled to -15 C. internal temperature. The dropping funnel contains a solution of 101.515 g. (0.50 mol) of isophthalic acid dichloride in 227 g. of N-methylcaprolactam. The dissolved acid chloride is dropped during 5 minutes into the cooled diamine solution whilst stirring.
  • the RSV of the poly-m-phenyleneisophthalamide obtained amounts to 1.1.
  • EXAMPLE 6 For a comparative solution experiment, a poly-mphenyleneisophthalamide is used which had been made according to the known process of boundary surface polymerization in cyclohexanone/water. After Washing and drying the polymer had a RSV of 1.67 (0.2% in concentrated sulphuric acid at 20 C.). g. of the polymer is dissolved whilst stirring at 5060 C. in 85 g. of N-methylcaprolactam. After 2-3 hours there is formed a colorless, clear, highly viscous solution which can be used for spinning fibres, for casting foils, and for impregnating and which, on standing for weeks at room temperature, undergoes no change.
  • Example 3 According to Example 3, a salt-free 16% by weight solution of poly-m-phenyleneisophthalamide in N-methylcaprolactam is made.
  • the polyamide has an RSV of 2.08.
  • Example 3 A salt-free 16% by weight solution is produced in accordance with Example 3 containing poly-m-phenyleneisophthalamide in N-methyl-caprolactam, having an RSV of 2.55.
  • the solution having a viscosity of 920 poises at 20 C. is forced with a feed rate of 3.6 ml. per minute through a nozzle with 100 holes whose circular bores have a diameter of 80, into a precipitating bath consisting of a 35% by weight aqueous calcium chloride solution.
  • the filaments pass through the precipitation bath heated to 90-100 C. with an immersion length of 160 cm. and are drawn off by draw ofi rollers running with a circumferential speed of 11 111.
  • the filaments pass through a clean Water washing bath of 80 cm. length at 20 C. and are finally wound on a perforated spool with a circumferential speed of 22 in. per minute. In this bath there is thus stretching at a ratio of 2:1.
  • the spool is then washed by insertion into a water bath at 30-50 C. for 2 hours and then dried in vacuo (0.5 mm. Hg).
  • the dried yarn is then stretched in a ratio of 2:1 in a hot stretch thread twisting machine (Rieter 10 J5/l0a) at 305 C. with a drafting speedof 25m. per minute, in which the yarn receives 2700 turns per metre.
  • a yarn with the following properties is obtained:
  • Example 1 For the polycondensation of poly-m-phenyleneisophthalamide the apparatus described in Example 1 is used. The same quantities of starting materials are used, as solvent however N-ethylcaprolactam is used.
  • the diamine solution produced is clear and stirrable at an internal temperature of 17" C.
  • the cooling bath temperature at the time of addition of the solid isophthalic acid dichloride is 24 C.
  • the acid chloride at first remains undissolved and is suspended in the reaction mixture by stirring.
  • the polycondensation is started by raising the bath temperature to 5 C.
  • the reaction begins at an internal temperature of 12 C. and proceeds more slowly than in N-methylcaprolactam.
  • the maximum temperature of +35 C. is only reached 11 minutes from the beginning of the reaction.
  • the further working up of the condensation product takes place in the way described in Example 3.
  • the RSV of the product obtained amounts to 1.58.
  • the filtered salt free solution is still completely clear after storing for 5 weeks.
  • EXAMPLE 10 The manufacture of p0ly-m-phenyleneisophthalamide takes place according to Example 9. As solvent 3,3,5-trirnethyl-N-methylcaprolactam is used. The polycondensation reaction starts only at an internal temperature of 2 C. and then progresses rapidly. After 40 seconds the maximum temperature of 35 C. is reached. The temperature rise produced exothermically is small, however, and amounts only to 34 C. The Working up of the condensation mixture takes place as in Example 3.
  • the RSV of the polymer obtained amounts to 2.15.
  • EXAMPLE 11 The procedure is as in Examples 1 and 9, with the difference that as solvent N-methyl-oenanthyl lactam is used.
  • the polycondensation starts at 0 C., which is produced by raising the cooling bath temperature, originally 24 C. to +1 C.
  • the maximum temperature of +41 C. is reached in 60 seconds.
  • the viscosity of the reaction mixture increases very considerably; it remains, however, stirrable in all phases of the polycondensation.
  • Example 3 The neutralization and pressure filtration take place as in Example 3. A salt-free polyamide solution is obtained which remains clear even after weeks.
  • the RSV of the polymer amounts to 1.85.
  • the polyarnide exhibiting a reduced specific viscosity of at least 1.0 based on a 0.2 gram solution of the polyamide in 100 milliliters of concentrated sulfuric acid at C., the improvement which comprises dissolving the polyamide in a salt-free solvent of the Formula II:
  • R is an alkyl having 1 to 4 carbon atoms and n is an integer from 5 to 7; to obtain a stable, salt-free solution.
  • a stable, salt-free, neutral solution capable of being spun or cast into shaped articles such as fibers and films by conventional wet spinning techniques which comprises 12 a linear aromatic polyamide at least of which has repeating structural units of the Formula I:
  • the polyamide exhibiting a reduced specific viscosity of at least 1.0, based on a 0.2 gram solution of the polyamide in milliliters of concentrated sulfuric acid at 20 C., and a salt-free solvent of the Formula II:
  • R is an alkyl group having 1 to 4 carbon atoms and n is an integer from 5 to 7.
  • polyamide is a polycondensate of m-phenyl diarnine and isophthaloyl chloride, the polycondensation being carried out in said lactam.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Polyamides (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
US00220898A 1971-02-09 1972-01-26 Process for the salt free manufacture of articles from linear aromatic polyamides in a lactam solvent Expired - Lifetime US3767609A (en)

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CH186671A CH510718A (de) 1971-02-09 1971-02-09 Verfahren zur Herstellung von Polyamid-Formgebilden

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AT (1) AT326262B (it)
AU (1) AU458542B2 (it)
BE (1) BE778415A (it)
BR (1) BR7200456D0 (it)
CA (1) CA1005942A (it)
CH (1) CH510718A (it)
FR (1) FR2124296A1 (it)
GB (1) GB1375251A (it)
IE (1) IE36037B1 (it)
IT (1) IT948322B (it)
NL (1) NL143261B (it)
PL (1) PL84727B1 (it)
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0695776A3 (de) * 1994-04-06 1997-06-11 Hoechst Ag Verfahren zur Herstellung von Fasern oder Filmen, danach hergestellte Fasern oder Filme
US10745579B2 (en) 2018-08-31 2020-08-18 International Business Machines Corporation Extrudable poly(propylene) compositions

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0695776A3 (de) * 1994-04-06 1997-06-11 Hoechst Ag Verfahren zur Herstellung von Fasern oder Filmen, danach hergestellte Fasern oder Filme
US5646234A (en) * 1994-04-06 1997-07-08 Hoechst Ag Production of fibers or films using specific forming solutions and the fibers of films obtainable thereby
US10745579B2 (en) 2018-08-31 2020-08-18 International Business Machines Corporation Extrudable poly(propylene) compositions

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CH510718A (de) 1971-07-31
GB1375251A (it) 1974-11-27
ATA59572A (de) 1975-02-15
BE778415A (fr) 1972-05-16
FR2124296A1 (it) 1972-09-22
AT326262B (de) 1975-12-10
AU458542B2 (en) 1975-01-31
PL84727B1 (it) 1976-04-30
NL7114351A (it) 1972-08-11
CA1005942A (en) 1977-02-22
DE2204075A1 (de) 1972-10-05
IE36037L (en) 1972-08-09
IT948322B (it) 1973-05-30
IE36037B1 (en) 1976-08-04
AU3833672A (en) 1973-08-02
SE375105B (it) 1975-04-07
NL143261B (nl) 1974-09-16
SU410591A3 (it) 1974-01-05
BR7200456D0 (pt) 1973-05-24

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